Natural gas has increasingly become attractive as fuel for internal combustion engines. In one type of engine, a small quantity of injected liquid diesel fuel is compression ignited to in turn ignite a larger charge of natural gas. Delivery of these two fuels to the combustion space was originally contemplated utilizing two completely separate systems for supplying the two different fuels to the combustion space. More recently, there has been interest in attempting to supply the two fuels to the engine cylinder from a single fuel injector. For instance, U.S. Pat. No. 6,073,862 shows a fuel injector with the ability to inject gaseous and liquid fuels through two separate sets of nozzle outlets of a single fuel injector. This reference teaches the use of dual concentric check valve members for controlling the injection of the two separate fuels. While the art of fuel injectors shows several different fuel injectors with dual concentric checks for various purposes such as mixed mode (HCCI and diesel) systems, staged fuel injectors and others, the problems associated with the ability to mass produce consistently operating fuel injectors with dual concentric check valve members has resulted in few, if any, fuel injectors reaching the market with dual concentric check valve members for any reason. Thus, one might expect potentially insurmountable problems in attempting to manufacture a commercially viable dual fuel injector employing concentric check valve members.
The present disclosure is directed toward one or more of the problems set forth above.